Moisture removal system



April 26, 1960 R. E. SMALL 0; MOISTURE REMOVAL SYSTEM Filed Nov. 19, 1956 ATTORNE IN V EN TOR.

- United States Patent MOISTURE REMOVAL SYSTEM Application November 19, 1956, Serial No. 623,246

12 Claims. 01. 34-69) This invention relates to a system fordiminishing the quantity of moisture carried on one or both surfaces of a web, and more especially to a moisture removal sys- 'tem useful, for example, in removing the water from the surfaces of a waxpaper web following a water quenching of the wax to set the same.

In the above paragraph, a utilitarian environment for the invention was set forth as the removal of moisture from a web of waxpaper. It will be apparent to those familiar with that art that reference is being made to a wet Wax system of making waxpaper; and in describing the invention in detail, reference will be made to the removal of water from a waxpaper web, which appears thereon as part of the waxpaper forming process, because the invention is particularly adapted to such use. Generally, in a wet wax system, a paper web is coated on each side thereof with melted wax, and after the de position of the wax coating, the web is passed into a reservoir containing cooled water which functions to solidify the wax and thereby set it on each side of the paper web.

It is necessary following the water-quenching step to remove moisture collections or portions thereof on the web, and a number of systems have been employed in the past to effectuate that result. However, all of the known systems have serious disadvantages, and there is a need for an improved moisture removal system and particularly for a system which removes a controlled amount of water, allowing a predetermined amount of water to remain in the sheet to provide flexibility and other advantages. One of the main objects of this invention is to provide such a system for the removal of controlled amounts of water. to provide in a wet wax system for forming waxpaper, a means for removing moisture from the wax-coated paper web following the Water quenching step of solidifying the wax, that utilizes a plurality of coacting para.m

eters-each adjustable independently and in connection with the otherswhereby a refined control of the moisture removal is effectuated.

' Still another object of the invention is in the provision of a water removal system useful, for example, in the wax coating of paper webs, and in which the moisture is removed from the wax-coated web by the combination of a doctoring action and a suction action, both controlled in a timed relation with respect to the action thereof on any given area of the web, and in which means are provided for selectively adjusting the doctoring action, the suction action and the time of application of each. Yet a further object is that of providing in a system as heretofore described, a pair of rolls adapted to have a hardened wax-coated web passed thereabout, and in which -the 'w'rap or extent of engagement of the web with the surface of the rolls is adjustable, in which the rotational "speed of the rolls is adjustable with respect to the speed of travel of the web so as to provide a doctoring action, and in which the rolls are provided with slots extending "from edge to-edge ofthe'web, each in communication Another object of the invention is,

Patented Apr. 26,

with a vacuum system, the suction of which is adjustable to control the adherence of the web to the surface of the rolls. Yet a further object is to provide a system as described which is basically rotary in character and thereby adapted for high speed operation; which employs a limited number of rolls whereby the cost of-the system is minimized; which has the advantage of being self-cleaning so that streaks and spots in the web are avoided; which has reduced wearing of the components thereof because of the speed relation between the rolls 7 and moving web; which is adjustable to accommodate webs of different widths; which reduces the prevalency of web breakage because of the adjustability of the various control parameters; which is easily and inexpensively maintained, etc. Additional objects and advantages will appear as the specification develops.

An embodiment of the invention is accompanying drawing, in which- Figure 1 is a side view partly in elevation and partly in section showing the components of the system; and Figure 2 is a vertical sectional view taken along the line 2-2 of Figure 1.

Figure 1 illustrates a continuous paper web 10 which is drawn from a parent roll (not shown) having each side thereof coated with wax in any suitable manner, as, for example, by drawing the same through a bath of wax or between wax-applicating rolls, etc. The wax may be deposited in liquid form and then solidified in a quenching operation as by passing it through a water bath or other cooling means.

" The controlled water removal is accomplished by means of a pair of rollers 17 and 18 which are. carried respectively on shafts 19 and 20 equipped with intermeshing gears 21 and 22. Any suitable means for driving the shafts may be employed. In the illustration given, a shaft 23, which may be the shaft of a vvariable'speed motor or the shaft of any power-driven device, is equipped with a pinion 24 meshing with the gear 22.

The axle 19 of the roller 17 is mounted within an elongated slot 25 so that it may be shifted to the right or left, as viewed in Fig. l, to respectively decrease or increase the wrap-around or extent of engagement of the web 10 with both the rollers 17 and 18.

The web 10 is coated on each side thereof with a layer of wax, and in being passed through the water bath 14 each side of the web has a moisture collection thereon. Therefore, the two rollers 17 and 18 are employed, one for removing the moisture from each of the respective sides of the. web. In construction and function, the rollers 17 and 18 are identical, and the vertical sectional illustration of the roller 18 shown in Fig. 2 of the drawing is applicable also to the roller 17, and the detailed description of the roller 18 which will now be set forth with particular reference to Fig. 2 will be understood, then, to apply also to roller 17.

The roller 18 has a plurality of arcuately-spaced-apart passages 28 extending longitudinally therethrough along illustrated in the 'an arch spaced inwardly from the cylindrical surface of 'V-shaped. At opposite ends of the roll 18 are thearcuate manifolds 31 and 32 which define, respectively,chambers 33 and 34 therein thatare adapted to communicate with the respectively opposite ends of the passages 28.

line 49 with that chamber.

As has been brought out before, the roll 18 is rotatable, but the manifolds 31 and 32 are stationary and are 'in tight abutting relation with the respective ends of the roll. Therefore, as'the roll rotates, the various passages ,28 are progressively moved into open communication with the manifold chambers 33 and 3.4. In open communica- ;tion with the chamber 33 .is a conduit 35-having a bypass valve 36 interposed therein. The conduit 35 is adapted to communicate with a source of vacuum or suction, and the by-pass valve 36 permits adjustment of the :suction by admitting a selected portion of atmospheric air through the inlet 37. It is apparent that the reduced pressure created between suction line 35 will be present in the chamber 33, passages 28 communicating therewith -.in the channels 29 of these passages, and in the chamber 34. If desired, an additional suction line 38 may be provided in open communication with the chamber 34 'so as to more uniformly and rapidly create low pressure areas throughout the entire length of the various passages 28, and more particularly in the channels 29 thereof. Within the manifolds 31 and 32 are provided ex- ;ternally adjustable segments 3ft, as indicated in Fig. 1, .and thus providing the chambers with timing means for the timing of the vacuum.

Occasionally, Wax collections may become lodged, particularly in the channels 29 and bores 29a thereof. Ordinarily, however, the suction applied to these components is sufficient to withdraw wax deposits and prevent the collection thereof. However, advantageously, a valve 39 may be interposed in the conduit 33, and communicating with that valve is an inlet conduit 40 adapted to com- .municate with a source of air under pressure. The valve 39 may be adjusted to connect the suction line 38 with .the chamber 34 or, alternatively, to connect the pressure The application of air pressure will function to blow off any wax that tends to col- 'lectdue to the doctoring action of the rolls, which will be described in greater detail hereinafter.

It will be noted in Figure 2 that the web is not as Wide as the roll 13, and the roll is equipped with width guides 41 and 42 that are dimensioned so as to account for the difference between the length of the roll and the width of the web. The guides 41 and 42 may take any of a number of varied forms, but ordinarily are simply bands that may be placed over the cylindrical surface of the roll adjacent the ends thereof and tightened in positionthereon. It will be apparent that a number of guides .may be provided of different width so as to accommodate the webs of varying widths.

In operation of the moisture removal system, a paper Web 10 after being coated on each side thereof with wax,

It is wrapped in tion over the roll 18. The rolls rotate in opposite directions-the roll 17 rotating in a clockwise direction, and the roll 18 in a counterclockwise direction. Means (not shown) will, of course, be provided for advancing the web 10.

The vacuum or suction lines 35 and 38 will be con- .nected to appropriate vacuum pumps to create low pressure areas in the passages 28 (and in their channels) that are in communication with the vacuum or manifold chambers. Thus, the vacuum will suck the web 10 into tight engagement with the surface of the rolls 17 and 18. This .suction will, of course, draw off moisture from .the areas of the web that are in .alignment with the channels,.29. .Ihe rapidity with which the moisture is drawn off and .theiorce .of engagement of the web with .the surfaces of .the rolls willdepend upon the quantitative value :of the vacuum, and that value canbe adjusted bymeans of the by-pass valve 36. That is, if a direct communicationis provided between the line 35 and the chamber 33, a greatersuction will be applied than .if the valve isadjusted so as to use a portion of the vacuum in drawing "in air through the inlet 37.

Another feature of adjustment resides in the position of theroll 17 which is horizontally movable within the limits defined by the slot 27. If, the roll is moved to the left, it will be apparent that more of the web 10 will be brought into engagement with the cylindrical surface of both the roller 17 and roller 18. The opposite condition prevails if the roller 17 is moved toward the right.

Preferably, the rollers 17 and '18 are rotated at a speed that is slightly less than the rate of travel of the web 10by a value of about 10%, for exampleso that a doctoring action occurs between the rolls and the web. This doctoring action is effective to scrape off moisture from the web, and has the additional advantage of progressively changing the areas of the web in alignment with the specific channels 29. Therefore, a passage and channel 29, in moving from the initial end of the manifold chambers 33 and 34 to the terminal ends thereof, will be in aligned, facing relation with a progressively different area of the web and will, of course, apply suction thereto for removing moisture collections therefrom.

If webs of various width are to be run through the system, guide bands 41 and 42 of the correct size are used so as to close off the end portions of the channels .29 which are not in use and thereby prevent the loss of suction. The channels extend from end to end of the roll and, of course, from edge to edge of the web 10, and therefore the suction, doctoring action and wrap-around .are applicable to the full Width of the web. If the channels andlports 30, etc., become obstructed with wax collections caused particularly by the doctoring action of the rolls, the valves 36 and 39 are adjusted so as to permit air under pressure to be admitted through the line 40 for blowing out those elements.

It will be apparent that a plurality of control factors or parameters are provided in the system-the most important being the extent of wrap-around of the web 10 with respect to the rolls 17 and 18, the suction or'vacuum present in the channels 29, and the speed of the rolls which influences the doctoring action. The rolls provide a rotary system that, as is well known, is conducive to .high speed operation, yet only a minimum number of rolls are employed to accomplish the water removal from both sides of-the web. Since the water removal occurs across the entire width of the web, fluttering thereof is eliminated. Since there is a small differential in the rate of movement of the web 10 and rolls 17 and 18, wear on the rolls is held to a minimum-with a consequent savings in maintenance expense-and web breakage is sharply minimized. In addition, the system is substantially self-cleaning, as has been brought out before, whereby streaks and spots that frequently mar waxpaper webs are eliminated.

While the system is useful especially in connection with the controlled moisture removal from waxpaper webs that have been processed in a wet wax system, it is applicable .to' other operations in which liquid is removed or drawn .mto a sheet as, for example, in the treatment of paper .ingirom thespirit and scope of the invention.

1.1111, moisture, removalapparatus wherein va moistened web is advancedfrom one station to another, a roll rotatably mounted andextending-across the path of movement of said Web for engagement with a moistened surface thereof, said roll being provided with a channel extending lon itudinally h reof in open communication with its cylindrical surface, means for providing a suction in said channel to draw off moisture from the web area aligned therewith, and means for rotating said roll at a rate such that its surface moves relative to the web.

2. The apparatus of claim 1 in which said channel increases progressively in depth toward the center of said roll, and in which the suction is initiated at the area of greatest depth of the channel.

3. The apparatus of claim 1 in which means are provided for mounting the roll for lateral adjustment in directions toward and away from the surface of said web for selectively determing the surface area of said roll engaged by said web.

. 4. In moisture removal apparatus of the character described for use in removing moisture from the surface of a web advancing at a predetermined rate from one station to another, a rotatably mounted roll provided with a plurality of circumferentially spaced channels extending longitudinally of said roll and opening into the cylindrical surface thereof, means for creating a suction at said channels to draw said web against the surface of said roll, and means for rotating said roll at a rate such that the surface velocity thereof differs slightly from the velocity of movement of said web.

5. The apparatus of claim 4 in which said roll is provided with a plurality of arcuately spaced passages extending longitudinally thereof, a passage provided for each of said channels, said roll being provided with a port for each of said channels communicating the same with its respective passage manifold means being provided at least at one end of the chamber communicable with a changing plurality of said passages as said roll rotates, and means associated with said chamber for applying suction to said chamber whereby a suction is present in a plurality of said passages at any given time.

6. The apparatus of claim 4 in which said roll is adjustably movable in directions toward and away from the surface of said web to alter the extent of wrap-around of the web with the roll.

7. In a system for removing moisture from the surfaces of a moistened web traveling from one station to another, a pair' of rotatably mounted rolls parallel with each other and extending transversely across the path of travel of such web for engagement with opposite sides thereof, means for rotating said rolls at a rate such that the surface velocities thereof differ from the velocity of the web engaging the same to provide relative movement therebetween, each of said rolls having a plurality of spaced apart channels opening onto the cylindrical surfaces thereof, a manifold for each of said rolls adjacent an end thereof and defining a chamber, means communicating a plurality of said channels of each of said rolls simultaneously with its manifold chamber, and means for providing a suction at each manifold for establishing reduced pressures in said channels.

8. The apparatus of claim 7 in which control means are provided for adjusting the amount of suction present in the manifold chambers.

9. The structure of claim 7 in which means are provided for supporting one of said rolls for movement in directions toward and away from the surface of a web engaged thereby so that the extent of wrap-around of a web on each of said rolls is adjustable.

10. The apparatus of claim 7 in which means are provided forestablishing an air blast in said channels to blow out deposits collecting therein from webs engaged thereby.

11. In moisture removal apparatus of'the character described wherein a moistened web is advanced from one station to another at a predetermined rate, at least one rotatably mounted roll extending across the path of advance of said web for engagement with the surface thereof, said roll being so positioned with respect to the path of said web as to be partially wrapped by said web, said roll having a channel extending longitudinally thereof p in the outer cylindrical surface thereof, means for rotating said roll at a rate such that the surface velocity thereof differs from the predetermined rate of travel of said web for causing relative movement between'said channel and the surface of the web engaged thereby, whereby moisture collects in said channel as it contacts the web, and means for removing moisture collections deposited in said channel from said web.

12. In combination, a liquid quench tank for a moving wax-surfaced web, a rotatably mounted roll extending across the path of said web for partial wrapping engagement therewith upon issuance of said web from said tank, means for rotating said roll at a rate such that the surface velocity thereof differs slightly from the velocity of said web to cause relative movement between the engaged surface portions of said web and said roll, a longitudinally-extending channel in the surface of said roll, said channel being effective to collect moisture from the web issuing from the quench tank, and means for removing liquid transferred to said channel from said web.

References Cited in the file of this patent UNITED STATES PATENTS 

